IP Library Granted Patent US 9,679,778
Granted Patent B2
US 9,679,778 · App. 15/154,467 · Granted Jun 13, 2017

Methods of forming memory cells with air gaps and other low dielectric constant materials

Inventors: Minsoo Lee (Boise, ID); Akira Goda (Boise, ID)
Assignee: Micron Technology, Inc.
H01L21/28273H01L21/28282H01L21/764H01L27/11519H01L27/11556H01L27/11565H01L27/11582H01L29/4234H01L29/42324H01L29/66825H01L29/7889
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Quick Facts
Patent No.
US 9,679,778
App. No.
15/154,467
Granted
Jun 13, 2017
Kind
B2
Abstract

Various embodiments include apparatuses and methods of forming the same. One such apparatus can include a first dielectric material and a second dielectric material, and a conductive material between the first dielectric material and the second dielectric material. A charge storage element, such as a floating gate or charge trap, is between the first dielectric material and the second dielectric material and adjacent to the conductive material. The charge storage element has a first surface and a second surface. The first and second surfaces are substantially separated from the first dielectric material and the second dielectric material, respectively, by a first air gap and a second air gap. Additional apparatuses and methods are disclosed.

Claims (38)

1. A method of forming an apparatus, the method comprising:

forming an opening through a first dielectric material, a second dielectric material, and a conductive material disposed between the first dielectric material and the second dielectric material;

recessing the conductive material laterally from the opening to form a recessed control gate and to expose portions of the first dielectric material and the second dielectric material; and

forming a charge storage element adjacent to the recessed control gate, opposing surfaces of the charge storage element being substantially in contact with an air gap.

2. The method of claim 1 , further comprising, prior to forming the charge storage element, forming a dielectric material over at least portions of exposed areas of the conductive material that are proximate to the opening.

3. The method of claim 2 , wherein the dielectric material is a thermally-grown silicon dioxide.

4. The method of claim 1 , further comprising, prior to forming the charge storage element, forming portions of a third dielectric material over the exposed portions of the first dielectric material and the second dielectric material, the control storage element being later formed between portions of the third dielectric material.

5. The method of claim 4 , further comprising substantially removing portions of the third dielectric material to form the air gaps between the charge storage element and the exposed portions of the first dielectric material and the second dielectric material.

6. The method of claim 4 , further comprising, prior to forming the charge storage element, forming a fourth dielectric material over at least portions of the third dielectric material.

7. The method of claim 6 , wherein the fourth dielectric material is formed from a material that is dissimilar to the third dielectric material, the fourth dielectric material to act as an etch stop for the third dielectric material.

8. The method of claim 1 , further comprising, prior to forming the charge storage element, at least partially filling the opening with a semiconductor material.

9. The method of claim 8 , further comprising removing at least a portion of the semiconductor material to form a second opening.

10. The method of claim 1 , further comprising, prior to forming the charge storage element, overfilling the opening with a semiconductor material.

11. The method of claim 10 , further comprising removing at least a portion of the semiconductor material to form a second opening.

12. The method of claim 1 , further comprising forming a tunnel dielectric over the air gaps.

13. A method of forming an apparatus, the method comprising:

forming a first dielectric material;

forming a second dielectric material;

forming a conductive material between the first dielectric material and the second dielectric material;

forming an opening through the first dielectric material, the second dielectric material, and the conductive material;

recessing the conductive material laterally from the opening to form a recessed control gate and to expose portions of the first dielectric material and the second dielectric material; and

forming a charge storage element adjacent to the recessed control gate, opposing surfaces of the charge storage element being substantially in contact with an air gap.

14. The method of claim 13 , wherein the charge storage element has substantially vertical sidewalls.

15. The method of claim 13 , further comprising forming the charge storage element to have a toroidal shape, the toroidal shape having a cross-section that is substantially rectangular.

16. The method of claim 13 , further comprising forming the charge storage element to have a toroidal shape, the toroidal shape having a cross-section that is substantially square.

17. The method of claim 13 , wherein the apparatus is formed in a trench such that the apparatus has non-enclosing features that is open on two ends.

18. The method of claim 13 , further comprising forming the apparatus to have an aspect ratio of feature depth to opening size to be about 30 to 1.

19. A method of forming an apparatus, the method comprising:

forming a first dielectric material and a second dielectric material substantially parallel to one another and to a surface of a substrate, the first dielectric material being more proximate to the substrate than the second dielectric material;

forming a conductive material between the first dielectric material and the second dielectric material;

forming an opening through the second dielectric material, the conductive material, and at least partially through the first dielectric material;

recessing the conductive material laterally from the opening to form a recessed control gate; and

forming a charge storage element adjacent to the recessed control gate, the charge storage element having a first surface and a second surface, the first surface and the second surface being substantially separated from the first dielectric material and the second dielectric material by dielectric materials having a low dielectric constant.

20. The method of claim 19 , further comprising forming a third dielectric material over the charge storage element and over the low dielectric constant material.

21. The method of claim 20 , further comprising forming a thickness of the conductive material to a thickness of the third dielectric material to be from about 10-to-1 to about 4-to-1.

22. The method of claim 20 , further comprising wherein the third dielectric material comprises a tunnel material.

23. The method of claim 19 , further comprising forming a second conductive material within the opening and over the third dielectric material.

24. The method of claim 23 , wherein the second conductive material is to be a channel for a string of memory cells.

Assignments (6)
RELEASE OF SECURITY INTEREST Recorded Nov 12, 2019
From: JPMORGAN CHASE BANK, N.A., AS COLLATERAL AGENT
To: MICRON TECHNOLOGY, INC.; MICRON SEMICONDUCTOR PRODUCTS, INC.
Reel/Frame 051028/0001 →
RELEASE OF SECURITY INTEREST Recorded Oct 9, 2019
From: MORGAN STANLEY SENIOR FUNDING, INC., AS COLLATERAL AGENT
To: MICRON TECHNOLOGY, INC.
Reel/Frame 050676/0782 →
RELEASE OF SECURITY INTEREST Recorded Jul 20, 2018
From: U.S. BANK NATIONAL ASSOCIATION, AS AGENT
To: MICRON TECHNOLOGY, INC.
Reel/Frame 046635/0634 →
SECURITY INTEREST Recorded Jul 13, 2018
From: MICRON TECHNOLOGY, INC.; MICRON SEMICONDUCTOR PRODUCTS, INC.
To: JPMORGAN CHASE BANK, N.A., AS COLLATERAL AGENT
Reel/Frame 047540/0001 →
SUPPLEMENT NO. 1 TO PATENT SECURITY AGREEMENT Recorded Aug 26, 2016
From: MICRON TECHNOLOGY, INC.
To: U.S. BANK NATIONAL ASSOCIATION, AS COLLATERAL AGENT
Reel/Frame 039841/0207 →
SUPPLEMENT NO. 1 TO PATENT SECURITY AGREEMENT Recorded Aug 25, 2016
From: MICRON TECHNOLOGY, INC.
To: MORGAN STANLEY SENIOR FUNDING, INC., AS COLLATERAL AGENT
Reel/Frame 039824/0681 →
Continuity (3)
Continuation 14825947 · Aug 13, 2015
Division 13222367 · Aug 31, 2011
Related Publication 20160254159A1 · Sep 1, 2016